Going to chime in again, just cause I'm sitting here bored.
Soon after I started riding mountain bikes (20+ years ago) I got into clipless. I had my share of fall-on-my-side-cause-I-can't-clip-out moments but after a few months I got pretty good at clipping in and out. When I took up DHing in the '90s I kept with clips and had no problem. That was until I had a nasty crash. I’ve had my share of bad crashes but this one was different. My feet didn’t come out of the pedals and I ended up doing a faceplant into some rocks, which resulted in me being airlifted to the hospital. After that I got spooked from using clips on my DH bike and switched to flats. I still rode XC clipped in but when it came to my downhill bike the last thing I wanted was to be glued to the pedals. It was much easier to bail from the bike on flats. But, there was one problem. I had been riding clipless so long that I never learned how to properly control my bike without being clipped in. I didn’t have any type of BMX background so I flat out (no pun intended) sucked at riding with flat pedals. My feet wouldn’t stay on and I couldn’t bunny hop to save my life. My buddies were all riding flats on their DH bikes and catching air as if they were clipped in. I knew I had to learn to master flats if I wanted to continuing downhilling so I swapped out the clips on my XC bike and rode that way for a few months. At first even hoping up onto a curb was awkward but I soon started to feel more comfortable and eventually got good enough that I could hop onto a park bench. When I switched back to clips on my XC bike it was like a whole new experience. My riding skills had really improved from riding flats that being clipped in just added another level of control I hadn’t realized before. It was eye opening.
For anyone who is serious about trail riding and who has already mastered clipless, I strongly suggest you learn to ride flat pedals. It will make you a better rider. For those of you who ride flats and have never gotten into clipless I recommend you learn to ride clipless because it does improve control, especially on rough climbs.
I guess my answer is to learn to ride both ways. This way you can switch according to where, when and what you plan on riding.